Index: test/CodeGen/PowerPC/reloc-align.ll
===================================================================
--- test/CodeGen/PowerPC/reloc-align.ll	(revision 0)
+++ test/CodeGen/PowerPC/reloc-align.ll	(revision 0)
@@ -0,0 +1,34 @@
+; RUN: llc -mcpu=pwr7 -O1 < %s | FileCheck %s
+
+; This test verifies that the peephole optimization of address accesses
+; does not produce a load or store with a relocation that can't be
+; satisfied for a given instruction encoding.  Reduced from a test supplied
+; by Hal Finkel.
+
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+%struct.S1 = type { [8 x i8] }
+
+@main.l_1554 = internal global { i8, i8, i8, i8, i8, i8, i8, i8 } { i8 -1, i8 -6, i8 57, i8 62, i8 -48, i8 0, i8 58, i8 80 }, align 1
+
+; Function Attrs: nounwind readonly
+define signext i32 @main() #0 {
+entry:
+  %call = tail call fastcc signext i32 @func_90(%struct.S1* byval bitcast ({ i8, i8, i8, i8, i8, i8, i8, i8 }* @main.l_1554 to %struct.S1*))
+; CHECK-NOT: ld {{[0-9]+}}, main.l_1554@toc@l
+  ret i32 %call
+}
+
+; Function Attrs: nounwind readonly
+define internal fastcc signext i32 @func_90(%struct.S1* byval nocapture %p_91) #0 {
+entry:
+  %0 = bitcast %struct.S1* %p_91 to i64*
+  %bf.load = load i64* %0, align 1
+  %bf.shl = shl i64 %bf.load, 26
+  %bf.ashr = ashr i64 %bf.shl, 54
+  %bf.cast = trunc i64 %bf.ashr to i32
+  ret i32 %bf.cast
+}
+
+attributes #0 = { nounwind readonly "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
Index: lib/Target/PowerPC/PPCAsmPrinter.cpp
===================================================================
--- lib/Target/PowerPC/PPCAsmPrinter.cpp	(revision 185327)
+++ lib/Target/PowerPC/PPCAsmPrinter.cpp	(working copy)
@@ -679,7 +679,26 @@ void PPCAsmPrinter::EmitInstruction(const MachineI
       OutStreamer.EmitRawText(StringRef("\tmsync"));
       return;
     }
+    break;
+  case PPC::LD:
+  case PPC::STD:
+  case PPC::LWA: {
+    // Verify alignment is legal, so we don't create relocations
+    // that can't be supported.
+    // FIXME:  This test is currently disabled for Darwin.  The test
+    // suite shows a handful of test cases that fail this check for
+    // Darwin.  Those need to be investigated before this sanity test
+    // can be enabled for those subtargets.
+    if (!Subtarget.isDarwin()) {
+      unsigned OpNum = (MI->getOpcode() == PPC::STD) ? 2 : 1;
+      const MachineOperand &MO = MI->getOperand(OpNum);
+      if (MO.isGlobal() && MO.getGlobal()->getAlignment() < 4)
+        llvm_unreachable("Global must be word-aligned for LD, STD, LWA!");
+    }
+    // Now process the instruction normally.
+    break;
   }
+  }

   LowerPPCMachineInstrToMCInst(MI, TmpInst, *this);
   OutStreamer.EmitInstruction(TmpInst);
Index: lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- lib/Target/PowerPC/PPCISelDAGToDAG.cpp	(revision 185327)
+++ lib/Target/PowerPC/PPCISelDAGToDAG.cpp	(working copy)
@@ -1530,6 +1530,14 @@ void PPCDAGToDAGISel::PostprocessISelDAG() {
       if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(ImmOpnd)) {
         SDLoc dl(GA);
         const GlobalValue *GV = GA->getGlobal();
+        // We can't perform this optimization for data whose alignment
+        // is insufficient for the instruction encoding.
+        if (GV->getAlignment() < 4 &&
+            (StorageOpcode == PPC::LD || StorageOpcode == PPC::STD ||
+             StorageOpcode == PPC::LWA)) {
+          DEBUG(dbgs() << "Rejected this candidate for alignment.\n\n");
+          continue;
+        }
         ImmOpnd = CurDAG->getTargetGlobalAddress(GV, dl, MVT::i64, 0, Flags);
       } else if (ConstantPoolSDNode *CP =
                  dyn_cast<ConstantPoolSDNode>(ImmOpnd)) {